The present invention relates to a golf ball having numerous dimples on the surface thereof. More particularly, it relates to a golf ball which, through optimization in the shape of the dimples, has an improved aerodynamic performance and a stable flight performance.
For a golf ball which has been hit to travel a long distance, it is important that the ball itself have a high rebound and that air resistance during flight be reduced by dimples arranged on the surface of the ball. A variety of approaches from the standpoint of, e.g., type, shape, and surface coverage on the ball can be taken for improving the dimples. For example, the aerodynamic performance is improved by increasing the surface coverage of the dimples to stabilize the trajectory of the ball.
When a large number of dimples are formed on a golf ball, the dimple sizes, volumes and other characteristics that determine the cross-sectional shapes of the dimples have in the past been quantified by using circular arcs to mathematically describe the cross-sectional shapes of the dimples, and changing these variables as appropriate. However, this process took time to find the numerical values that fit the desired dimple characteristics such as size and volume, in addition to which it grew complicated.
U.S. Pat. No. 4,681,323 describes what might be referred to as a “double” dimple shape composed of a recessed dimple within which there is formed another recess. Such dimples enable the dimple volume to be enlarged without increasing the dimple diameter, and thus make it possible to extend the distance traveled by the ball.
However, in a double dimple shape, the cross-sectional shape of the dimple resulting from the combination to two differing circular arcs is complex. Numerically quantifying such shapes is thus complicated, as a result of which it takes time to determine the optimal volume occupancy VR.